Configuration

Cache aliases

The caches module allows to setup cache configurations and then use them either using an alias or retrieving the config explicitly. To set the config, call caches.set_config:

To retrieve a copy of the current config, you can use caches.get_config or caches.get_alias_config for an alias config.

Next snippet shows an example usage:

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from pycached import caches, SimpleMemoryCache, RedisCache
from pycached.serializers import StringSerializer, PickleSerializer

caches.set_config({
    'default': {
        'cache': "pycached.SimpleMemoryCache",
        'serializer': {
            'class': "pycached.serializers.StringSerializer"
        }
    },
    'redis_alt': {
        'cache': "pycached.RedisCache",
        'endpoint': "127.0.0.1",
        'port': 6379,
        'timeout': 1,
        'serializer': {
            'class': "pycached.serializers.PickleSerializer"
        },
        'plugins': [
            {'class': "pycached.plugins.HitMissRatioPlugin"},
            {'class': "pycached.plugins.TimingPlugin"}
        ]
    }
})


def default_cache():
    cache = caches.get('default')  # This always returns the same instance
    cache.set("key", "value")

    assert cache.get("key") == "value"
    assert isinstance(cache, SimpleMemoryCache)
    assert isinstance(cache.serializer, StringSerializer)


def alt_cache():
    # This generates a new instance every time! You can also use `caches.create('alt')`
    # or even `caches.create('alt', namespace="test", etc...)` to override extra args
    cache = caches.create(**caches.get_alias_config('redis_alt'))
    cache.set("key", "value")

    assert cache.get("key") == "value"
    assert isinstance(cache, RedisCache)
    assert isinstance(cache.serializer, PickleSerializer)
    assert len(cache.plugins) == 2
    assert cache.endpoint == "127.0.0.1"
    assert cache.timeout == 1
    assert cache.port == 6379
    cache.close()


def test_alias():
    default_cache()
    alt_cache()

    cache = RedisCache()
    cache.delete("key")
    cache.close()

    caches.get('default').close()


if __name__ == "__main__":
    test_alias()

When you do caches.get('alias_name'), the cache instance is built lazily the first time. Next accesses will return the same instance. If instead of reusing the same instance, you need a new one every time, use caches.create('alias_name'). One of the advantages of caches.create is that it accepts extra args that then are passed to the cache constructor. This way you can override args like namespace, endpoint, etc.